Most undisturbed peatlands sequester carbon, and rising levels of atmospheric nitrogen deposition may have the potential to destabilize this function, possibly resulting in an increased release of carbon dioxide into the atmosphere. It is therefore of vital importance to investigate further the link between atmospheric nitrogen deposition and carbon dynamics in exposed ecosystems such as peatlands. The work described in this thesis aimed to elucidate the impact of increasing nitrogen on aspects of carbon turnover in peatlands. Using a long-term field-based experiment, I tested the effects of 4 years of ammonium and nitrate addition (8, 24 and 56 kg N ha<sup>-1</sup> y<sup>-1</sup>) on the fate of newly photosynthesised carbon by plants and the turnover of labile and recalcitrant carbon. A second set of experiments undertaken in the laboratory assessed the use of plant wax analysis as potential biomarkers of past changes in vegetation and carbon status in peat. Overall, this work has shown that the form of nitrogen (ammonium versus nitrate) is a crucial component of atmospheric pollution and must be taken into consideration when investigating or predicting effects of reactive nitrogen on peatlands. In addition, nitrogen addition affected the fate of newly synthesised carbon differently in <i>Eriophorum vaginatum </i>and <i>Calluna vulgaris, </i>revealing the importance of considering plant traits when investigating environmental changes in terrestrial ecosystems. Furthermore, it has led to the development of an investigative tool for further exploration of the historical effects of atmospheric nitrogen deposition on vegetation an carbon content in peatlands.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:540475 |
| Date | January 2009 |
| Creators | Currey, Pauline M. |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=165545 |
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